Why not start with something simple to build?
Most designs used quarter wave labyrinth, just go for you feel most comfortable with and with contemporary crossover improvements perhaps?_________________I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

I'm not interested in easy costructions, because I had made many of them. I want to make TL speakers & that's why ask this question. The crossover is built in pre-amplifier, & I don't want to change it. It works good.

Sorry that the previous links did not work, I've mislaid my original scans from Hi-Fi News but these were discovered on the internet._________________I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

A "transmission line" is a mistake in system name. It is a resonant quarter wavelength pipe which is normally made very lossy for loudspeaker reinforcement use. There is no one correct way of making a pipe. e.g. look at the variation in organ pipes.

Agreed! Calling the pipes or labyrinths a TL is a nonsense, but one often does so as almost everybody else does...
All pipes have resonances no matter how well damped they are, they will exhibit standing waves at various frequencies which by definition interact with the output from the bass speaker cone depending in which way it is moving. I would never build another “TL” no matter how good it sounds; many do not sound all that clever when presented with real bass as from an organ for example. It is an eye opener when doing a sweep of frequencies and monitoring as to what the output can be up to.

I am amazed to this day as to how good products from PMC can sound, I guess that somehow they have avoided the laws of physics somewhere along the line... _________________I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

The Professional Monitor Company, better known as PMC Ltd., is a British loudspeaker manufacturer, established in 1990. The company's products are widely used within domestic settings, professional studios and other HF-fi applications. Most if not all their loudspeakers are folded lines, labyrinths or TLs depending on what you like to call them.
Have a look at their domestic and professional range, available either passive or in active form. Also make subwoofers.

Link:https://pmc-speakers.com/_________________I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

A related question...
What do you thing about using the Atkins design to build two enclosures with simply a B139 each and the low pass section of the xover to function as subs?

I am using a pair of R107 equivalent at the moment and reading about bass management and taming room modes, 4 subwoofers at the 4 corners is optimum. I'm thinking of putting the extra two enclosures at the rear corners.

I have some data of different TL authors, but can't to choose the optimal project (recommended by somebody). The closed box maybe? But it was the last my construction with two " face-to-face" woofers. It's not interesting now

This site is down a lot but I'd urge some of you who still have the stamina and willpower to build loudspeakers to visit it.
The last few pages are certainly worth it!
Link: https://engineering.purdue.edu/ece103/LectureNotes/SRS_Speaker_and_Enclosure_Intro.pdf_________________I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill